1. Field of the Invention
This invention relates to an image compensating method, and more particularly, the invention relates to an image compensating method that can use the correctional gray level value of complete black or white, which is measured from the patterns of longitudinal black and white, complete white, or complete black, and that can compare the correctional gray level values with the theoretical gray level values of the complete black or white, so as to adjust the brightness of the scanned image.
2. Description of Related Art
FIG. 1 is a perspective view schematically illustrating a conventional scanner 100. As shown in FIG. 1, the scanner 100 includes a base 102 and a cover 104, in which one end of the cover 104 is connected with an end of the base 102 via a hinge device 106 so that the cover 104 can be opened and closed on the base 102.
The base 102 includes a top 108, a scanning platform 110, a chassis 114, a transverse complete white pattern 116, and the top 108, which is located on the base 102. The scanning platform 110 can also be situated on the top 108, so as to align a document 112. Wherein, the chassis 114 is located inside of the base 102 in a movable manner, so that the chassis 114 can be moved along the direction of arrow 105 in order to scan the document 112, as shown in FIG. 1, when the cover 104 and the base 102 are closed. In addition, the transverse complete white pattern 116 is located on an inner wall of the top 108 near an end of the scanning platform 110 and is used to allow the scanner 100 to perform a correction on the image before the chassis 114 starts to scan the document 112. A gray level correction value is obtained and is used as the standard for adjusting the gray level value of the image when the chassis 114 of the scanner 100 begins scanning the document 112.
It should be noted that when the chassis 114 of the scanner 100 scans the document 112, the gray level value of the image could be adjusted according to the correctional gray level value. However, the intense light needed for the scanning operation and the scattering light in the environment during the scanning process can affect the gray level value of the image after the chassis 114 scans the document to obtain the gray level value of the image. Due to the faulty condition created by the light brightness error, the obtained gray level value of the image cannot be adjusted according to the correctional gray level value. This also causes a distortion on the image obtained by the scanner and consequently has a large effect on the image quality.